High pressure liquid chromatography (HPLC) systems sometimes require the dilution of a sample before the sample is injected into the mobile phase flowing to a chromatography column. For example, the sample may be dissolved in a strong solvent that may interact with the mobile phase and negatively affect chromatography. Normally, it is desirable to focus the sample at the head of the chromatographic column; however, strong solvents can prevent at least some of the sample from being retained at the head of the column.
Sample dilution can be performed manually by a skilled technician; however, it is not always practical for a technician to be available. In many instances, the technician and equipment for performing dilutions are located at an inconvenient distance from the HPLC system, resulting in significant delay. Moreover, there exist the risks of contamination and human error in the dilution process. In addition, the additional inconvenience of tracking transported samples is often necessary.